Device for controlling a surface treatment installation, in particular for the automotive industry

ABSTRACT

The invention concerns a system comprising at least a multiaxial machine ( 2 ), each axis being equipped with motor means, provided with items of equipment ( 4 ) such as for example a sprayer and corresponding sensors and actuators. Said system comprises: means for supervising the installation including at least a computer ( 14 ) provided with display means and means for inputting data; at least a programmable computer ( 1 ) for managing the axes of the machines and their items of equipment; a server ( 10 ) that can be common to several installations, for programming spraying tables. A first computer network ( 18 ) connects the server to the programmable computer(s) ( 12 ) for managing the machines ( 2 ) and to the means ( 14 ) for supervising the installation. A second computer network ( 20 ) connects the programmable computers ( 12 ) for managing the machines ( 2 ) to the sensors and actuators of said machines ( 2 ).

[0001] The present invention relates to a device for controlling asurface treatment installation, in particular for the automotiveindustry.

[0002] In the automotive industry, a surface treatment installationintended, for example, for painting bodyworks carried and moved by aconveyor comprises, for example, a set of six machines which areintended to coat the side walls of the bodyworks and a machine, knownalso as the “overhead machine” intended to coat surfaces which lieroughly horizontally. Each of the six lateral machines is equipped witha sprayer, while the overhead machine comprises three distinct sprayers.Such an installation operates in synchronism with the conveyortransporting the bodyworks. It also has a booth provided with verticalventilation and with a system for recuperating excess coating product.

[0003] The command and control device for such an installation comprisesa command and control system common to the entire installation andcommand and control systems for each of the machines and other elementsof the installation.

[0004] The command and control system common to all of the sprayersmakes it possible in particular to identify the type of bodyworkentering the zone of the installation and to track this bodywork untilit leaves the zone. It may be pointed out that several bodyworks may liein the same zone and may be painted at the same time. This system alsokeeps the installation safe through the various sensors with which it isequipped, and coordinates the operation of the sprayers and theinterfaces with the booth, the conveyor, etc.

[0005] The command and control systems for each of the machines allow inparticular control over the kinematics of the corresponding machine andcontrol over the spraying parameters of the sprayer(s) it supports. Thekinematics and the spraying parameters are specific to each bodyworkbeing treated.

[0006] A programmable industrial controller may, for example, beassociated with each machine or other element of the installation. Eachof these controllers is controlled by another programmable industrialcontroller commanding and controlling the entire operation. This“master” controller is itself connected to a supervisor which may be inthe form of a computer of the personal computer type. If severalinstallations are present in one and the same factory, these command andcontrol systems may be organized into a network and a common computerconnected to this network is then used for programming the variousparameters for each of the installations.

[0007] The “master” programmable controller allows information to bereceived from the various sensors and, through an appropriate means,determines what type of bodywork is arriving in the zone of theinstallation with which it is associated. This controller has, inmemory, for each of the types of bodywork, a table known as the“spraying table” which contains all the orders of positioning of each ofthe machines and other elements and the setting of each of the sprayerswith respect to the advancement of the bodywork along the conveyor. Atregular intervals, each interval corresponding, for example, to themovement of the bodywork along the conveyor by a predetermined distance,the machines and sprayers require new settings because the bodywork hasmade progress through the installation. After each interval of time, thecorresponding orders are thus sent to each of the programmableindustrial controllers corresponding to a machine or to another element.These controllers are also known as “slave” controllers as opposed tothe “master” controller.

[0008] The spraying tables for each of the bodywork types are programmedon the computer mentioned earlier used for programming. For a bodyworkof given shape, these tables consist in entering, for various positionsof the bodywork in the installation, the various orders corresponding,for example, to the positions of the various axes of each machine, tothe flow rate of treatment product for each of these sprayers, to theelectrical voltage applied, etc. Once the spraying tables have beenprogrammed they are loaded into the “master” controller using disks orthe like.

[0009] The supervisor for its part allows the progress of the process tobe monitored through its various stages and also allows particularorders to be sent to a machine, particularly in the adjustment ormaintenance phase. This supervisor has a screen to allow the process tobe displayed and a keyboard for inputting orders and/or modifications.

[0010] The time needed to optimize these spraying tables for each of thebodyworks is very high. What is actually required is for a great manypoints to be entered so that the kinematic envelope of each of themachines is close to the shape of the bodywork. This is true for each ofthe bodyworks and there are generally on average 20 bodyworks at eachproduction factory. As a result, the number of points in the sprayingtables is limited to about 100 depending on the complexity of theexterior shape of the bodywork. In addition, bearing in mind the varioustypes of paint, adjustments to the settings of the sprayers are needed.As a result, the number of tables is further multiplied for each of theshades and tables are obtained which, in total, contain of the order ofabout 10000 programmed points.

[0011] In addition, it is necessary to test these tables in real life,that is to say on a bodywork. This test and setting phase may last froma few days to several weeks. It is costly in terms of time and also interms of operating costs in that it uses up coating and cleaning productand in that it soils the installation and therefore requiresmaintenance. Furthermore, in car plants, old installations are oftenreplaced with new ones during the summer shutdown period. There are thenfour weeks in which the old installation has to be taken down, theinfrastructures have to be modified, the new installation has to beassembled, commissioned and tested empty and then finally theapplication has to be set up so that it will be ready to start in fullproduction with the minimum of rejects. The testing and setting phaserepresents the lengthiest and the most uncertain part of thecommissioning of a new installation.

[0012] This phase can be shortened in that there now exist meansallowing spraying tables to be simulated prior to the on-site testphase.

[0013] It is thus an object of the present invention to provide acommand and control device that allows a further reduction in the costof the test phases by reducing the time needed for these phases and/orthe operating costs associated with them. This system willadvantageously also allow modifications to be made more easily when anew type of bodywork, or work piece that is to be treated, appears orwhen the characteristics of the sprayed product change.

[0014] To this end, the system proposed by the invention is a commandand control system for a surface treatment installation comprising atleast one multi-axis machine, each axis being equipped with drive means,fitted with equipment such as, for example, a sprayer and withcorresponding sensors and actuators, this system having:

[0015] means allowing the installation to be supervised and comprisingat least one programmable computer provided with display means and withmeans allowing data to be entered,

[0016] at least one programmable computer for managing the axis of themachines and their equipment, and

[0017] a server, which may be common to several installations, allowingspraying tables to be programmed,

[0018] and this system being characterized in that a first computernetwork connects the server to the programmable computer(s) managing themachines and to the means for supervising the installation, and in thata second computer network connects the programmable computer(s) managingthe machines to the sensors and actuators of the machines.

[0019] The first computer network allows in particular the downloadingof spraying tables. These can then be programmed online, thus making itpossible to reduce the installation downtime. The second network for itspart allows settings and measurements needed for various control loopsregulating parameters of the installation to be carried out.

[0020] The invention applies to installations intended for sprayingcoating product onto a bodywork but may also be applied to installationsfor removing dust or to other installations provided with multi-axismachines.

[0021] Advantageously, the computer(s) managing the axes of machinesincorporates (incorporate) a numerical control managing the axes withinterpolation, for example circular interpolation. In this way, thesynchronization of the various parameters of the equipment and thekinematic slaving is facilitated. In this case, it may be advantageousto provide, for the drive means associated with the axes of the machinespreferably comprising speed variators, a specific third computer networkconnecting these variators to the programmable computer(s) managing theaxes of the machines. This third network allows the position of themachines and of their equipment to be read and the motors operatedaccordingly.

[0022] The command and control system according to the inventionpreferably also includes means for identifying the work piece that is tobe treated, providing the interface with the booth and the conveyor andalso managing safety precautions. These identification, interface andsafety means may be in the form of a set of sensors and actuators commonto all the machines and connected to the means for supervising theinstallation.

[0023] The command and control system advantageously has a fourthcomputer network connecting the computer for supervising theinstallation to the factory computer network. This network allows thetype of work piece that is to be treated to be transmitted. The commonsensors and actuators are, for example, on the same network as thesensors and actuators specific to each of the machines.

[0024] To save time when commissioning on site, the serveradvantageously has simulation means allowing the application of aspraying to a work piece that is to be treated to be displayed.

[0025] In order to allow remote intervention to diagnose breakdowns andpossibly solve them, the server is, for example, equipped with a modemallowing it to communicate with a computer situated remotely and alsoequipped with a modem. This modem makes it possible, from theremotely-situated computer, to diagnose or operate each of the sensorsand actuators of the installation.

[0026] In any event, the invention will be clearly understood with theaid of the description which follows, with reference to the appendedschematic drawing which, by way of examples, depicts several forms ofembodiment of such a command and control system.

[0027]FIG. 1 is a schematic view of a command and control systemaccording to the invention,

[0028]FIG. 2 schematically shows an alternative form of embodiment ofthe system of FIG. 1 as regards an installation,

[0029]FIG. 3 shows, like FIG. 2, another alternative form of embodimentof the system of FIG. 1, and

[0030]FIG. 4 shows a fourth alternative form of embodiment of a commandand control system according to the invention.

[0031]FIG. 1 shows one embodiment of a command and control system for aset of surface treatment installations. Each installation is notdepicted in detail in the drawing. The various installations aredepicted schematically by boxes in chain line. In this description, itmay be considered that this is, for example, an installation intendedfor coating motor vehicle bodyworks, these being carried and moved by aconveyor. The installation is made up for example of two sets of threemachines located one on each side of the conveyor. These six machinesare intended to paint the roughly vertical lateral faces of the bodyworkadvancing with the conveyor. These machines are also known as lateralmachines. Each of these machines carries an automatic sprayer of coatingproduct. It is a machine with several degrees of freedom that may bequalified as a multi-axis machine. To each degree of freedom, or axis,there corresponds a motor which acts on the machine and directly orindirectly causes the sprayer to move and/or modifies its orientation inspace. To treat the surfaces of the car bodywork which are roughlyhorizontal, use is made, for example, of a machine known as the overheadmachine, which carries three sprayers. The overhead machine also hasseveral degrees of freedom and the sprayers it carries can move one withrespect to the other. All these machines comprise sensors and actuatorsfor achieving the various movements of the machine and determining itsexact position.

[0032] To limit paint splashes, a booth is associated with theinstallation. The bodywork for painting lies in the booth which isrelatively well sealed during the spraying operations. In and around thebooth there are a certain number of common actuators and sensors formoving the various parts and elements and for determining theirposition.

[0033] The purpose of the command and control system is to manage allthe elements that make up the installation in such a way as to obtainfault-free painted motor vehicle bodyworks. To do that, all the sprayingparameters of the sprayers need to be managed and the movement of thebodywork on the conveyor needs to be coordinated with respect to themovement of the sprayers. Furthermore, the control system must alsoensure that the installation is safe.

[0034] Each of the figures schematically depicts two machines 2, on eachof which one sprayer 4 is mounted. Each of these machines has a set ofspecific sensors and actuators which are not individually depicted. Eachmachine 2 thus symbolizes all the sensors and actuators specific to it.

[0035]FIG. 1 also shows four computers 10, 12, 14, and 16 eachcomprising a central processor and a screen, to each of which a keyboardcan be connected for entering data. These computers are, for example,personal computers commonly known as “PCs”.

[0036] In FIG. 1, a first computer 10 will be known hereinafter asserver. A second computer 12 will be known hereinafter as operatingcomputer. The computer bearing the reference 14 will, for its part, beknown as the supervisor, while the fourth computer 16 will be knownhereinafter as the central computer.

[0037] The server 10 is a computer which may be common to severalinstallations of the type of those described hereinabove. It is able tomanage a certain number of identical installations or alternativelyseveral installations which all differ from one another. The server 10allows the spraying tables, in which the kinematics and the operatingparameters of the sprayers are predefined, to be programmed.

[0038] The operating computer 12 manages the axes of the machines 2 andthe sprayers 4. It first of all performs the functions of a programmableindustrial controller in that it provides the various axes of themachines 2 and the sprayers 4 with instructions corresponding topositions to be reached and to parameters (paint flow rate, electricalvoltage, etc.) to be set. In addition, to optimize the movement of thesprayers 4, the operating computer 12 incorporates the functions ofnumerical control so as, on the basis of the instructions received, tocarry out circular interpolation so as to obtain a movement of thesprayers 4 which best follows the shape of the bodywork that is to bepainted.

[0039] The supervisor 14 supervises the installation and forms aman/machine interface with the installation. It is therefore possiblefor a technician, using this computer, to monitor the parameters set inthe installation and the position of the various moving parts. Akeyboard allows data to be entered to allow a dialogue between the usertechnician and the installation. The supervisor 14 also incorporates thefunctions of a controller identifying the bodywork to be painted,providing the interfaces with the booth and the conveyor and managingthe various safety precautions implemented in the installation.

[0040] A first computer network 18 connects the server 10 to theoperating computers 12 and the supervisors 14. This computer network 18is common to all the installations served by the server 10. Inparticular it allows the spraying tables to be downloaded. It is then nolonger necessary as was generally the case in installations of the priorart to record the spraying tables on a computer medium (disk, CD-ROM,etc.) in order to be able to install them in the operating computer. Itis also possible, unlike the case with installations of the prior art,to program the spraying tables online. In addition, the server 10 hassimulation means allowing the application of a spraying table to abodywork that is to be treated to be displayed. This allows anappreciable time saving when commissioning the installation onsite.

[0041] A second computer network 20, at an installation, connects theoperating computer 12 to the machines 2. It allows the settings andmeasurements needed for the various control loops regulating theparameters envisaged in the system programming to be performed. Also onthis network are the sensors 6 and actuators 8 common to theinstallation.

[0042]FIG. 2 shows an alternative form of embodiment comprising a thirdnetwork 24, produced, for example, using optical fibers. In this figure,only the devices specific to one installation have been depicted. Eachmachine 2 of this installation comprises several speed variators 32 forcontrolling its various motors. Three of these variators 32 have beendepicted in FIG. 2. The third network 24 connects the operating computer12 to the machines 2 and more particularly to the variators 32controlling the motors thereof. These motors are “digital” electricmotors which, at each instance, give precise data regarding their speedand their position. The third computer network 24 allows thisinformation to be imparted to the operating computer 12 and the lattersends instructions to the variators 32 controlling the motors of themachines 2 on the basis of the information received.

[0043] A fourth computer network 22, present in all the alternativeforms depicted in the drawing, connects the supervisor 14 to the usercomputer network. As the installation is incorporated into a plantcomprising a great many other installations which have all to be managedtogether for correct plant operation, a link is established with theplant management system. This link is connected to the installation atthe level of the supervisor 14. The fourth network transmits to thelatter particularly the type of bodywork to be painted.

[0044] Furthermore, the server 10 is equipped with a modem 28 whichallows the server 10 to be placed in communication with the centralcomputer 16. The latter is also equipped with a modem 30. The centralcomputer is, for example, placed in the premises of the company whosetask it is to monitor and maintain the installation. By virtue of thelink by modems 28 and 30 it is possible to diagnose a fault remotelybecause the server has access to all the sensors via the operatingcomputer 12. This modem link allows a significant saving in time andcost because it can allow a problem to be solved without atroubleshooter having to be sent out. This modem link also allows thespraying tables to be written on the central computer, tested on asimulator and then, once the spraying tables have been optimized, theycan be downloaded to the server 10.

[0045] Like FIG. 2, FIG. 3 shows a third alternative form of embodimentin which the supervisor is in fact made up of a computer 34 and of aprogrammable industrial controller 36 which is separate. Theprogrammable industrial controller 36 then takes responsibility for thecommand and control of the sensors 6 and actuators 8 common to theinstallation, and the computer 34 takes responsibility for displayingand inputting commands. The computer 34 and the programmable industrialcontroller 36 are both connected to the fourth computer network 22,connected to the user computer network.

[0046]FIG. 4 shows an alternative form of embodiment in which thefunctions of the operating computer 12 and of the supervisor 14 in FIGS.1 and 2 are grouped together into one and the same computer.

[0047] The command and control systems described hereinabove make itpossible to achieve significant time savings when commissioning apainting installation and when fault finding. They also allow greaterflexibility because they make modifications within the manufacturer'srange easier. It becomes easier to add a new shade of paint or a newtype of bodywork to the spraying tables.

[0048] The invention also encompasses other alternative forms ofembodiment within the scope of the attached claims.

[0049] Thus, for example, the command and control system according tothe invention applies not only to an installation comprising paintsprayers but also may apply to the field of powder coating and to aninstallation comprising machines for removing dust.

[0050] The modem connection between a central computer and the commandand control system is optional and it would not be departing from thescope of the invention if this connection were not provided.

[0051] In place of the operating computer described and depicted in FIG.1, it is possible to provide several operating computers. These are notnecessarily a computer of the “PC” type but may for example also beprogrammable computers of the controller type.

[0052] The description hereinabove anticipates an operating computerincorporating the functions of numerical control and carrying outcircular interpolation of the instructions received in order to controlthe sprayers. The system according to the invention does not necessarilyinclude these numerical control functions and where it does includethem, the sprayers are not necessarily controlled through circularinterpolation.

1. A command and control system for a surface treatment installationcomprising at least one multi-axis machine (2), each axis being equippedwith drive means, fitted with equipment (4) such as, for example, asprayer and with corresponding sensors and actuators, this systemhaving: means (14; 34, 36) allowing the installation to be supervisedand comprising at least one programmable computer (14; 34) provided withdisplay means and with means allowing data to be input, at least oneprogrammable computer (12) for managing the axis of the machines (2) andtheir equipment, and a server (10), which may be common to severalinstallations, allowing spraying tables to be programmed, characterizedin that a first computer network (18) connects the server (10) to theprogrammable computer(s) (12) managing the machines (2) and to the means(14; 34) for supervising the installation, and in that a second computernetwork (20) connects the programmable computer(s) (12) managing themachines (2) to the sensors and actuators of the machines (2).
 2. Thecommand and control system as claimed in claim 1, characterized in thatthe computer(s) (12) managing the axes of machines (2) incorporates(incorporate) a numerical control managing the axes with interpolation,for example circular interpolation.
 3. The command and control system asclaimed in claim 2, characterized in that the drive means associatedwith the axes of the machines (2) comprise speed variators (32) and inthat a third computer network (24) connects these variators (32) to theprogrammable computer(s) (12) managing the axes of the machines (2). 4.The command and control system as claimed in one of claims 1 to 3,characterized in that it also includes means for identifying the workpiece that is to be treated, providing the interface with the booth andthe conveyor and also managing safety precautions.
 5. The command andcontrol system as claimed in claim 4, characterized in that theidentification, interface and safety means are in the form of a set ofsensors (6) and actuators (8) common to all the machines (2) andconnected to the means (14; 36) for supervising the installation.
 6. Thecommand and control system as claimed in one of claims 1 to 5,characterized in that the means for supervising the installationcomprise a computer (34) and a programmable controller (36).
 7. Thecommand and control system as claimed in claims 5 and 6, characterizedin that the set of common sensors (6) and actuators (8) are connected tothe programmable controller (36).
 8. The command and control system asclaimed in one of claims 1 to 5, characterized in that the means forsupervising the installation and the programmable computer(s) formanaging the machines (2) are incorporated into one and the samecomputer (12, 14).
 9. The command and control system as claimed in oneof claims 1 to 8, characterized in that the means (14; 34, 36) forsupervising the installation are connected to the computer network of afactory by a fourth computer network (22).
 10. The command and controlsystem as claimed in one of claims 1 to 9, characterized in that theserver (10) has simulation means allowing the application of a sprayingtable to a work piece that is to be treated to be displayed.
 11. Thecommand and control system as claimed in one of claims 1 to 10,characterized in that the server (10) is equipped with a modem (28)allowing it to communicate with a computer (16) situated remotely andalso equipped with a modem (30).